Die-casting is also referred to as a metal casting process. The die-casting is a precision casting method in which molten metal is injected into a steel mold cavity which is precisely machined so as to be completely matched with a required casting shape, thereby obtaining a casting having the same shape as the mold cavity.
Since the die castings have accurate dimensions, they have advantages, such as excellent mechanical properties, possibility of mass production as well as little or no finishing operations. Meanwhile, metals used in die casting are generally alloys of zinc, aluminum, tin, copper, magnesium, and the like, and after melted to molten metals, these alloys are injected into a mold cavity by a pressing apparatus, such as an air pressure device, a hydraulic pressure device and an oil pressure device, etc., to be quenched and then solidified.
The die castings manufactured through these processes are used in a variety of fields, and specially, employed in vehicle components, and also widely used in manufacturing of components, such as components of electronic instruments, optical instruments, vehicles, weaving machines, construction equipments and measuring instruments.
Meanwhile, Al—Si based alloys and Al—Mg based alloys with excellent castability are mainly used as aluminum alloys for die casting. Since Al—Si based alloys or Al—Mg based alloys have excellent castability, but a low thermal conductivity of 90-140 W/mK, the use thereof in heat dissipation components for electric devices, electronic devices, and vehicles requiring a high thermal conductivity of 160 W/mK or more is limited.
In heat dissipation devices requiring such a high thermal conductivity, while products cast with pure aluminum having a very high thermal conductivity of 220 W/mK or higher are partly used in rotors for electrical and electronic products, since pure aluminum has an excellent thermal conductivity, but a low tensile strength and low castability, its application in structural components requiring excellent mechanical properties as well as the excellent thermal conductivity is limited.
Therefore, for use in heat dissipation components for electric devices, electronic devices and vehicles, the development of aluminum alloys for die casting having a high thermal conductivity of 160 W/mK or more as well as excellent castability is acutely needed, but aluminum alloys having a thermal conductivity of 160 W/mK or more as well as excellent castability have not yet been developed. Therefore, Al—Si based alloys, Al—Mg based alloys, and the like with the thermal conductivity of 90-140 W/mK are currently used as aluminum alloys for die casting.